OBESITY IS NOT A RISK FACTOR FOR SIGNIFICANT ADVERSE OUTCOMES AFTER CARDIAC-SURGERY

Background Obese patients undergoing cardiac surgery are often thought to have prohibitive perioperative risk despite the lack of sufficient data to support this assumption. Methods and Results To assess the si gnificance of obesity as a risk factor in patients undergoing cardiac surgery, we analyzed data from 2299 patients undergoing procedures req uiring cardiopulmonary bypass from January 1, 1991, to December 31, 19 93. Obesity was defined by use of the body mass index, defined as weig ht in kilograms divided by height in meters squared. Potential adverse outcomes analyzed included operative mortality, deep sternal wound in fection, superficial sternal wound infection, infection at the sapheno us vein harvest site, stroke, renal failure, adult respiratory distres s syndrome, prolonged mechanical ventilation, pneumonia, sepsis, atria l arrhythmias, pulmonary embolism, need for early reexploration for bl eeding, and ventricular arrhythmias. To control for the confounding ef fects of other risk factors, we performed a multivariate logistic regr ession analysis. Potential covariates considered in the logistic model included age, sex, race, history of reoperation, congestive heart fai lure, prior myocardial infarction, renal failure, diabetes, hypertensi on, chronic obstructive pulmonary disease or stroke, and cardiopulmona ry bypass and aortic cross-clamp time. Twenty-five percent of patients (567/2299) were classified as obese. The results of the multivariate regression demonstrated that obesity was a risk factor only for-superf icial sternal wound infection (P<.001; odds ratio, 2.3), leg infection s (P=.005; odds ratio, 1.8), and atrial dysrhythmias (P=.04; odds rati o, 1.2). Notably, obesity did not predispose toward increased pulmonar y complications or deep sternal wound infection (P=.65). Conclusions W ith the exception of superficial wound complications and atrial dysrhy thmias, obesity is not a significant multivariate risk factor for adve rse outcomes. The results indicate that obese patients may safely unde rgo cardiac surgery with due attention to technical considerations des igned to minimize wound complications.